1. Field of the Invention
The present invention relates to an overheating protection apparatus of a scroll compressor, and particularly, to a scroll compressor having an overheating protection apparatus capable of improving reliability thereof and protecting it by bypassing discharged gas to a low pressure chamber if a temperature inside a compression chamber rises over an established temperature.
2. Description of the Background Art
In general, various types of compressor can be applied according to a compressing method, and a scroll compressor is usually used in an air conditioning system for which a miniature or a lightweight is required.
FIG. 1 is sectional view of a scroll compressor according to the conventional art.
The conventional scroll compressor is comprised of: a casing 106 respectively connected to a suction pipe 102 in which fluid is sucked and to a discharge pipe 104 through which a compressed fluid is discharged, and having a certain sealed space; a driving unit 108 set in a lower side of the casing 106, for generating a driving force; and a compressed unit 110 set in an upper side of the casing 106 and connected to the driving unit 108 and a rotating shaft 112, for compressing the fluid sucked in the suction pipe 102 by a rotation of the rotating shaft 112 to discharge it through the discharge pipe 104.
A main frame 114 is installed at the upper side of the casing 106 to rotatably support an upper side of the rotating shaft 112 and to support the compressed unit 110. A lower frame 116 is installed at the lower side of the casing 106 to rotatably support a lower side of the rotating shaft 112.
The driving unit 108 is comprised of a stator 122 fixed to the casing 106 in a circumferential direction and a rotor 124 set in an inner circumferential surface and fixed to the rotating shaft 112. If power is applied to the stator 122, the rotor 124 is rotated by an interaction between the stator 122 and the rotor 124 thereby to rotate the rotating shaft 112.
The compressed unit 110 is comprised of: a fixed scroll 128 having a fixed wrap of an involute shape therein and fixed to an upper side of the casing 106; and an orbiting scroll 132 having an orbiting wrap 130 of the involute shape therein, which corresponds to the fixed wrap 126, in order to have a certain compression chamber 118 between the fixed wrap 126 and the orbiting wrap 130 itself, supported at the main frame 114 to be orbited, and performing an orbiting movement during a rotation of the rotating shaft 112.
A discharging passage 136 is formed at the center of the fixed scroll 128 to discharge fluid compressed at the compression chamber 118 by an interaction between the fixed wrap 126 and the orbiting wrap 130. Further, a check valve 138 is installed at an upper side of the discharging passage 136 for preventing the discharged fluid from being flowed backward.
Moreover, a muffler 140 is mounted on an upper side of the fixed scroll 128 to reduce noise of gas discharged through the discharging passage 136, and an oldham ring 150 is installed between the orbiting scroll 132 and the main frame 114 for preventing the orbiting scroll 132 from being rotated.
Also, a temperature sensor (not shown) is installed to sense a temperature of the gas in the discharge pipe 104 discharging the compressed gas by being connected to a high pressure chamber 142 or inside the high pressure chamber 142, which is formed by the muffler 140 and into which the compressed gas is flowed. The temperature sensor cuts off power applied to the compressor if a temperature inside the high pressure chamber 142 rises more than an established value, and thereby the compressor can be protected.
As stated above, in the conventional scroll compressor, if power is applied to the stator 122, the rotor 124 is rotated by an interaction between the stator 122 and the rotor 124, and the rotating shaft 112 fixed to the rotor 124 is thus rotated in a forward direction. Thereby, the orbiting scroll 132 performs an orbiting movement by the rotation of the rotating shaft 112, so that the gas flowed in the compression chamber 118 by the interaction with the fixed scroll 128 is compressed to be flowed into the high pressure chamber 142 through the discharging passage 136. Thereafter, the gas flowed into the high pressure chamber 142 is discharged outside through the discharge pipe 104
At this time, the check valve 138 installed in the discharging passage 136 prevents the fluid discharged to a high pressure portion through the discharging passage 136 from being flowed backward to a low pressure portion.
However, as aforementioned, in the scroll compressor according to the conventional art, since a separate electric circuit (such as the temperature sensor to sense the temperature inside the high pressure chamber) should be constructed, manufacturing costs therefor can be increased. Furthermore, after the temperature inside the high pressure chamber is sensed by operating the temperature sensor, an operation of the compressor is stopped. As a result of this, an operation delay or an erroneous operation can be occurred, thereby damaging the compressor.